1.
Use the fundamental theorem of calculus, to evaluate (4 - 3) .
Solution:
∫12(x4 - 3x) dx
= ∫12x4 dx - 3 ∫12x dx
[Use Difference Rule of integration.]
= [x55]12 - 3 [x22]12
= [325-15] - 3 [4 / 2 - 1 / 2]
[Apply the limits of integration.]
= 31 / 5 - 9 / 2
= 62-4510 = 17 / 10
So, ∫12(x4 - 3x) dx = 17 / 10
Correct answer : (2)
2.
Use the fundamental theorem of calculus, to evaluate .
Solution:
∫0314x+3 dx
= 1 / 4 [ln | 4x + 3 | ]03
= 1 / 4 [ln 15 - ln 3]
[Apply the limits of integration.]
= 1 / 4 ln(15 / 3)
= 1 / 4 ln 5
So, ∫0314x+3 dx = 1 / 4 ln 5
Correct answer : (2)
3.
Use the fundamental theorem of calculus to evaluate, (3 + -3) .
Solution:
∫01(e3x + e -3x) dx
= ∫01e3x dx + ∫01e -3x dx
[Use Sum Rule of integration.]
= [e3x3]01 + [e-3x-3]01
= e33 - 1 / 3 + e-3-3 + 1 / 3
[Apply the limits of integration.]
= e33-e-33
= e3-e-33 = e6-13e3
So, ∫01(e3x + e -3x) dx = e6-13e3
Correct answer : (5)
4.
Use fundamental theorem of calculus, to evaluate (2 sin + 3 cos ) .
Solution:
∫0π/3(2 sin x + 3 cos x) dx
= 2 ∫0π/3sin x dx + 3 ∫0π/3cos x dx
[Use Sum Rule of integration.]
= 2 [- cos x ]0π/3 + 3 [sin x ]0π/3
= 2 [- cos π / 3 + cos 0] + 3 [sin π / 3 - sin 0]
[Apply the limits of integration.]
= 2 [- 1 / 2 + 1] + 3 [32]
= 1 + 332 = 2+332
So, ∫0π/3(2 sin x + 3 cos x) dx = 2+332
Correct answer : (4)
5.
Use fundamental theorem of calculus, to evaluate .
Solution:
Let x = 2 sin θ, dx = 2 cosθ dθ
At x = 0, θ = 0 and at x = 1, θ = π6.
∫0134-x2 dx
= ∫0π/634-4sin2θ(2 cosθ) dθ
= ∫0π/66cosθ2cosθ dθ
= ∫0π/63 dθ
= 3 [ θ ]0π/6
[Apply the limits of integration.]
= 3π6 = π2
So, ∫0134-x2 dx = π2
Correct answer : (3)
6.
Use the fundamental theorem of calculus, to evaluate cos2 .
Solution:
∫0πx cos2x dx
= ∫0πx[1+cos2x2] dx
= ∫0πx2 dx + ∫0πxcos2x2 dx
[Use Sum Rule of integration.]
= [x24 ]0π + ∫0πx cos2x2 dx
= π24 + 1 / 2 [[xsin2x2 ]0π - 1 / 2 ∫0πsin 2x dx]
[Use integration by parts.]
= π24 + [xsin2x4 ]0π - 1 / 4 [-cos2x2 ]0π
= π24 + πsin2π4 + 1 / 8 [cos 2π - cos 0]
[Apply the limits of integration.]
= π24 + 0 + 1 / 8 [1 - 1]
= π24
So, ∫0πx cos2x dx = π24
Correct answer : (4)
7.
Use the fundamental theorem of calculus to evaluate .
Solution:
∫01x2-1x2+1 dx
= ∫01x2+1-2x2+1 dx
[Rearrange the numerator.]
= ∫01x2+1x2+1 dx - ∫012x2+1 dx
[Use Difference Rule of integration.]
= ∫01dx - 2 ∫011x2+12 dx
= [ x ]01 - 2 [tan-1(x1) ]01
[Use ∫1x2+a2 dx = 1atan-1(xa) + C.]
= 1 - 2Tan -1(1)
[Apply the limits of integration.]
= 1 - π2 = 2-π2
So, ∫01x2-1x2+1 dx = 2-π2
Correct answer : (4)
8.
Use the fundamental theorem of calculus to evaluate .
Solution:
∫-30 xx2+5 dx
= 1 / 2 ∫-30 2xx2+5 dx
= 1 / 2 [ln | x2 + 5 | ]-30
[Use ∫f′(x)f(x) dx = ln | f(x) | + C.]
= 1 / 2 [ ln 5 - ln 14 ]
[Apply the limits of integration.]
= 1 / 2 ln (5 / 14)
So, ∫-30 xx2+5 dx = 1 / 2 ln (5 / 14)
Correct answer : (5)
9.
Use fundamental theorem of calculus to evaluate .
Solution:
Let 1 - 2x = t, - 2dx = dt, dx = - 1 / 2 dt
At x = 1, t = - 1 and at x = 2, t = - 3
∫1211-2x3 dx = - 1 / 2 ∫-1 - 31t13 dt
= - 1 / 2 ∫-1 - 3 t-13 dt
= - 1 / 2 [t2323 ]-1- 3
[Apply the limits of integration.]
= - 3 / 4 [(-3)23-(-1)23]
= - 3 / 4 ( 323 - 1)
So, ∫1211-2x3 dx = - 3 / 4 ( 323 - 1 )
Correct answer : (2)
10.
Use fundamental theorem of calculus, to evaluate 42(2 - 1)8 .
Solution:
Let 2x - 1 = t, 2 dx = dt, dx = dt2
At x = 0, t = - 1 and at x = 1, t = 1
∫014x2(2x - 1)8 dx = ∫-114(t+12)2t8dt2
= 1 / 2 ∫-11(t + 1)2t8 dt
= 1 / 2 ∫-11 (t2 + 2t + 1)t8 dt
= 1 / 2 ∫-11 (t10 + 2t9 + t8) dt
= 1 / 2 ∫-11 t10 dt + ∫-11 t9 dt + 1 / 2 ∫-11 t8 dt
= 1 / 2 [t1111 ]-11 + [t1010 ]-11 + 1 / 2 [t99 ]-11
= 1 / 2 [1 / 11 + 1 / 11] + [1 / 10 - 1 / 10] + 12[19+19]
[Apply the limits of integration.]
= 1 / 11 + 1 / 9
= 20 / 99
So, ∫014x2(2x - 1)8 dx = 20 / 99
Correct answer : (2)